Mike Kleijn (born 9 February 2005) is a Dutch professional footballer who plays as a midfielder for Eredivisie club Sparta Rotterdam.

[1] He worked his way up their youth sides, eventually captaining the U18s, and signed his first professional contract with them on 2 November 2020.

[2] In September 2022, he was named by English newspaper The Guardian as one of the best players born in 2005 worldwide.

[3] In his time with Feyenoord, Kleijn was included in the senior team's matchday squad only once, on 17 March 2022 in a Conference League game against Partizan, he remained on the bench in that game.

[4] On 12 April 2024, Kleijn signed a four-year contract with Sparta Rotterdam, beginning in the 2024–25 season.